The present invention relates generally to methods and devices for balancing vehicle wheel and tire assemblies. More particularly, the present invention pertains to methods and devices for calibrating an electronic wheel balancer apparatus.
Electronic wheel balancers are well known in the art. An example of a conventional wheel balancer 10 is shown in FIGS. 1 and 2. Typically, such a balancer 10 will include a housing or base unit 11 and an operator panel 12 mounted above the base unit. The base unit will contain control electronics, sensors, and an electric motor (not shown). The electric motor shaft 13 will extend laterally outside the base unit 11. A hub and faceplate assembly 14 will be affixed to the shaft to accommodate the mounting of a vehicle tire and wheel assembly for balancing.
A typical arrangement of a control system 20 for an electronic wheel balancer is shown in FIG. 6. An AC/DC power supply and safety module 21 is configured to receive power from the AC grid and then to distribute appropriate supply voltages and currents to the other balancer components. A control board 22 contains processing logic, data interface circuitry, and device interface circuitry to manage operation of the balancer, including performing the necessary balancer calculations. A user interface module 23 is coupled to the control board 22 and to the operator panel 12 so that the operator of the balancer can enter commands and receive prompts and information about operation of the balancer 10. A sensor module 24 is also coupled to the control board 22 to receive data from pressure or force imbalance transducers that is indicative of the balance conditions of a mounted wheel/tire assembly. An AC motor drive module 25 receives commands from control board 22 to provide for starting, stopping and speed control of the balancer motor.
Further details about, and embodiments of, an electronic wheel balancer that can be used as part of the present invention are shown in U.S. Pat. No. 7,882,738, the entire disclosure of which is incorporated herein.
Conventionally, electronic wheel balancers have used a wheel of certain size to calibrate the wheel balancer so that the balancer control logic can obtain the balance reference parameters before the user can use the wheel balancer to accurately balance a standard tire and wheel assembly.
What is needed is a method and apparatus for simplifying and fully automating the process for accurately calibrating an electronic wheel balancer.